7.5 The cost of placing a full-page colour advertisement and the circulation figures of nine magazines are: 9 43 16 17 19 13 20 44 35 Cost (000) Circulation (000) 135 2100 680 470 450 105 275 2250 695 (a) Which of these variables should be the dependent variable (Y), and why? (b) Plot a scatter diagram to portray the data. (c) Determine the Pearson correlation coefficient and assess its value